This section is from the book "A Guide To The Poisonous Plants And Weed Seeds Of Canada And The Northern United States", by Robert Boyd Thomson, H. B. Sifton. Also available from Amazon: A guide to the poisonous plants and weed seeds of Canada and the northern United States.
Anemone patens L., var. Wolfgangiana (Bess.) Koch.
Other Common Names: Prairie Crocus, Prairie Anemone, American Pulsatilla, Prairie Smoke.
Willing mentioned this plant as causing the death of sheep in Alberta, concluding that the trouble was due to the formation of felt-like balls (phytobezoars) of the hairs with which the whole plant is plentifully provided. In addition to this Pammel notes the presence of a very acrid poison, a crystalline substance anemonin, which, in the fresh plant, has given much inconvenience to collectors, producing an inflammation of the eyes and even blistering the skin where wet by the juice. The drug is used by homœo-pathists.
The Pasque Flower is one of the most beautiful plants of the prairie, but is not confined to this region, extending also to British Columbia. The large purplish flowers appear early in March on leafless stalks. Later the three-divided leaves appear. At first these and the stalk are covered with a dense coat of silky hairs which persist, but are more scattered, when the plant is fully grown. They form a valuable means of identification. The flower resembles in shape and size a small crocus and this has probably led to one of its popular names - the Prairie Crocus. It owes its beautiful crocus-like appearance to its coloured sepals,* the petals being small and stamen-like. The stamens and pistils are numerous, the latter, in fruit, forming a fluffy head, with the long styles developed into feathery tails.